1. Field of Invention
The present invention relates to a bowl for use in a centrifuge instrument.
2. Description of Prior Art
The containment system for a centrifuge instrument includes a vessel commonly called a bowl or a chamber. The bowl is usually surrounded by a guard ring that may itself be rotationally mounted with respect to the framework of the instrument. The bowl is formed of a substantially cylindrical sidewall having a planar floor portion. An outer flange is provided about the upper edge of the bowl whereby the bowl may be rigidly attached to the flamework.
The floor of the bowl has a central axial opening therein. The shaft upon which a centrifuge rotor is received projects through the opening in the floor of the bowl. The shaft is connected to and driven by any suitable source of motive energy.
A centrifuge rotor is mechanically secured to the top of the shaft for rotation within the confines of the bowl about a rotational axis extending through the shaft. A rotor fabricated from a suitable material such as aluminum will operate at a particular performance level for a specific number of cycles. This predetermined number of cycles is usually referred to as the cycle life of the rotor. After this predetermined number of cycles is reached the likelihood of a rotor disruption occurring due to material fatigue is greatly increased. When the rotor fails the rotor fragments will impact the sidewall of the bowl with a large amount of energy.
User error may cause another form of rotor disruption. If the rotor is not securely affixed to the shaft by the user it may become disengaged from the shaft during operation and impact against the sidewall of the bowl.
The containment system of the instrument is always designed to contain the energy of impact of the rotor or its fragments (if any) and to prevent the fragments from escaping the interior of the instrument.
The energy imparted to the sidewall of the centrifuge bowl can have devastating effects. In an improperly designed centrifuge a rotor failure can cause gross instrument movement, possibly injuring personnel who happen to be located nearby. In large floor model instruments the deformation and rotation of the guard ring allows the energy imparted by the rotor into the containment system to dissipate. By allowing the guard ring to rotate the amount of energy that is transferred to the instrument framework is greatly reduced.
In some models of tabletop centrifuge instruments insufficient available space precludes the provision of a rotatable guard ring surrounding the bowl. The bowl must, therefore, function as the guard ring. A tabletop instrument has the additional problem in that it is usually light in weight, which allows greater movement in the event of a rotor failure. Due to the potential for injury resulting from a rotor failure, the performance of rotors for use in a tabletop centrifuge instrument is usually degraded both to reduce its potential energy and to extend the life of the rotor.
Accordingly, it is believed advantageous to provide a centrifuge bowl that is adapted to separate itself from the framework of the centrifuge instrument in the event of a rotor failure, reducing the amount of energy that is transferred from the rotor to the centrifuge framework, thus preventing gross instrument movement.